Furnace roof door structure



Oct. 26, 1965 s. OLSSON FURNACE ROOF DOOR STRUCTURE 7 Sheets-Sheet 1 Filed Sept. 19, 1962 g WM 5 INVENTOR. JI EN 04:32am

,Wfia/ )6 TORNE Y5 Oct. 26, 1965 s. OLSSON FURNACE ROOF DOOR STRUCTURE 7 Sheets-Sheet 2:

Filed Sept. 19, 1962 INVENTOR. SVEN 04sso/v TOR NEYS

Oct. 26, 1965 s. OLSSON FURNACE ROOF DOOR STRUCTURE 7 Sheets-Sheet 3 Filed Sept. 19, 1962 INVENTOR. Jmsw 0L SSON Oct. 26, 1965 s. OLSSON 3,214,154

FURNACE ROOF DOOR STRUCTURE Filed Sept. 19, 1962 7 Sheets-Sheet 4 INVENTOR. yz/ew 04 562W Oct. 26, 1965 s. OLSSON FURNACE ROOF DOOR STRUCTURE 7 Sheets-Sheet 5 Filed Sept. 19, 1962 Oct, 26, 1965 s. OLSSON FURNACE ROOF DOOR STRUCTURE 7 Sheets-Sheet 6 Filed Sept. 19, 1962 M w 5 m A 0 Oct. 26, 1965 s. OLSSON FURNACE ROOF DOOR STRUCTURE 7 Sheets-Sheet 7 Filed Sept. 19, 1962 INVENTOR Svav 0455o- United States Patent 3,214,154 FURNACE ROOF DOQR STRUCTURE Sven Ulsson, Old Greenwich, Conn, assignor to Sunrod Manufacturing, New York, N.Y., a corporation of Delaware Filed Sept. 19, 1962, Ser. No. 224,691 18 Claims. (Cl. 263-46) The present invention relates to a furnace with a roof door structure for opening and closing an entrance to the furnace and means for sealing said entrance in closed position of said door structure.

In steel making, charging of a furnace, such as an open hearth furnace, has been one of the most time consuming operations. In the conventional method employed, steelboxes loaded with scrap, lime, etc. are inserted through side doorways in the furnace. It is estimated that this operation takes one hour or more for each 100 tons of furnace capacity, which at the present time may be 400 tons or more.

One object of the present invention is to provide a metal melting and refining furnace, such as an open hearth furnace, having new and improved roof door structure through which the furnace can be charged quickly, While protectively shielding the usual overhead crane structure and other equipment on top of the furnace, such as platforms, supports and operating gear for oxygen lances, against the heat escaping through the open doorway while the furnace is being charged.

In accordance with certain features of the present invention, the metal melting and refining furnace, such as an open hearth furnace is designed to be charged from the top. For that purpose, a section of the roof of the furnace is arranged as a door to be lifted in order to provide a large roof opening or doorway for charging the furnace. In most open hearth furnaces, a heavy crane girder runs over the top of the furnace in a vertical plane located approximately halfway between the furnace centerline and the back-wall of the furnace, this plane and girder being parallel to the longitudinal center line of the furnace. The movable roof section of the present invention extends only along a part of the width of the roof, so that it does not interfere with the crane girder over the other part of the roof section in open position of said roof section. Moreover, the movable roof section is hinged to swing open around an axis located near and parallel to the back edge of the section, so that when the section is opened, it is swung out of the way in front of the aforesaid crane girder in upright position, thus acting as a radiation shield for said crane girder.

It is important in a furnace for melting and refining metal to keep air infiltration to a minimum, in order to maintain a high temperature in the furnace and to keep the volume of the waste gases small. In practice, parts of such furnaces are, at least part of the time, operated with slight pressure, and it is thus also important to provide a gas-tight furnace to avoid losing any of the hot gases and consequently the heat contained by these gases. Also, the escape of such hot gases to the outside of the furnace may cause damage to structural members and to equipment located close to the furnace. Furthermore, such gases contain large quantities of dust and fumes, especially when oxygen is employed for refinement.

Another object of the present invention is to provide a furnace for melting and refining metal, such as an open hearth furnace, having a roof door for a roof doorway through which the furnace may be charged, provided with new and improved means for maintaining said doorway gas-tight when the door is closed in spite of misalignments in the door or in the structure of the furnace around the doorway, due to distortion resulting from severe service or accident.

3,214,154 Patented Oct. 26, 1965 "ice To attain the latter objectives, the door forming the movable section of the furnace roof has cooling tubes. Series of these tubes carried by the movable roof section extend along the periphery of the door in banks, and the fixed roof structure around the roof doorway has series of fixed cooling tubes arranged in banks in confronting relationship to the banks of tubes respectively carried by said movable roof section, to form junctures between edges of the movable roof section and adjoining edges of the fixed roof structure, bounded by these banks of cooling tubes. Carried by the movable roof section around its edges are sealing blocks, so designed and so supported therefrom by free play connections, as to cause said sealing blocks to extend across the junctures in seating engagement with the upper cooling tubes at these junctures, as the movable roof section is closed, thereby sealing said junctures against flow of air or gas therethrough. The connections between the sealing blocks and the movable roof section are such, that the sealing blocks can float under the action of gravity relative to the movable roof section automatically into seating engagement with the upper tubes at the junctures, irrespective of a misalignment between the movable roof section and the surrounding fixed roof structure, as the movable roof section is moved into closed position.

As another feature of the present invention, the confronting banks of cooling tubes at a juncture are Winding or devious to aid in impeding flow of gas or air through the juncture, and to offset the sealing blocks from direct furnace radiation. This offsetting of the sealing blocks from direct furnace radiation protects these blocks from extremely high furnace temperature and thereby prevents the movable sealing blocks from becoming overheated. This permits the sealing blocks to be made of ordinary hot-rolled carbon steel.

As a further feature, to meet the requirements of a gas-tight furnace and to protect the roof from the effect of high temperatures in the furnace, some of the cooling tubes are closely arranged in the form of a panel over the roof including the movable roof section, and a steel plate is placed on the outside of this tube panel contiguous therewith. The steel plate so located, is protected from direct radiation inside the furnace by these tubes, and by a layer of refractory attached to said tubes on the inner side, and by its contiguity to the tubes and will attain a temperature closely approaching that of the cooling medium in the tubes.

Various other objects, features and advantages of the invention are apparent from the following description and from the accompanying drawings, in which FIG. 1 is a transverse vertical section of an open hearth furnace for making steel, taken approximately along the lines 11 of FIG. 2, and shows somewhat diagrammatically an embodiment of the present invention;

FIG. 2 is a top plan view somewhat diagrammatic of a section of the furnace shown in FIG. 1;

FIG. 3 is a top plan cutaway view of the hinge part of the movable roof door section taken approximately along the lines 33 of FIG. 4;

FIG. 4 is a longitudinal vertical detail section of the roof of the furnace taken approximately along the lines 44 of FIG. 2 in a direction transverse to the longitudinal direction of the furnace as a whole;

FIG. 5 is a detail top plan view of the banks of cool ing tubes taken near one corner of the movable roof door section of the furnace;

FIG. 6 is a fragmentary top plan view showing the arrangement of the sealing blocks around three sides of the movable roof door section and taken approximately along the lines 66 of FIG. 4;

FIG. 7 is a detail section somewhat diagrammatic of the sealing block structure taken on lines 7-7 of FIG. 6;

FIG. 8 is a detail section somewhat diagrammatic of the sealing block structure taken on lines 38 of FIG. 6;

FIG. 9 is a perspective of one of the rear corner sealing blocks of the movable roof door section;

FIG. 10 is a perspective of one of the front corner sealing blocks of the movable roof door section;

FIG. 11 is a detail section taken across a juncture between a side of the movable roof door section and the adjoining fixed roof structure taken approximately along the lines 11-11 of FIG. 4;

FIG. 12 is an end view of one of the side sealing blocks shown in FIG. 11, and

FIGS. 13 to 16 show the side juncture structure corresponding to that shown in FIG. 11 with different degrees of alignment and misalignment between the door and the doorway structure, and illustrate the function of the movable sealing blocks in automatically adapting themselves into sealing position under all of these alignment or misalignment conditions.

Referring to FIGS. 1 and 2 of the drawings, the invention is shown somewhat diagrammatically applied to an open hearth furnace for making steel. FIG. 2 shows the top plan view of a section 10 of the furnace, the other sections not shown being somewhat similar to the section shown and being joined thereto along the dot and dash lines A.

The furnace comprises a frame with a roof supporting superstructure 11, which may be of any suitable construction, and which for the purpose of illustration, is shown diagrammatically as comprising a horizontal girder 12 at the rear of the furnace extending along said furnace and a horizontal girder 13 at the front of the furnace extending along the furnace. On the sides of each furnace section 10 are two horizontal beams 14 extending between and connected to the rear and front girders 12 and 13.

The furnace has a refractory lined hearth 15 with a rear wall 16, a front wall 17 having a charging doorway 18 in the front of each furnace section 10, closed by a vertically slidable door 19, as in the usual open hearth furnace, and a roof 20. The roof comprises a fixed section 21 extending from the rear of the furnace to an intermediate region of the roof to define a charging opening or doorway 22 in said roof at each furnace section 10. The fixed roof section 21 has its back 23 seated on and anchored to the rear furnace wall 16 and a part 24 near its front affixed to the fixed roof superstructure by any suitable means, as for example, by means of beams 25 and brackets 26, forming part of said fixed section and secured to the beams 14 forming part of said superstructure.

The furnace roof 20 also comprises a movable section 27 which is pivotally secured at its rear end to the fixed roof section 21 at axis 28 extending along the length of the furnace parallel to the back of the furnace, and which is supported at its front end on the front furnace wall 17 to form a door for the roof opening or doorway 22. The movable roof section 27 can be moved into open and closed position, and for purpose of simple illustration, it is shown liftable through a cable 30 and an overhead motor-driven pulley 31.

Supported above the roof 20 of the furnace is a heavy girder 32, which runs horizontally over the top of the furnace in a vertical plane located approximately halfway between the furnace longitudinal centerline and the rear wall of the furnace. This girder 32 supports rails 33 for a crane 34 movable on said rails along the length of the furnace and mounting a carriage (not shown) movable on said crane transverse of the furnace, as for example, for carrying ladles handling hot metal or for carrying charges or other loads, as required in steel furnace operations. Also, above the furnace roof 20' between the rear of the furnace and the longitudinal center line of the furnace is other equipment (not shown), such as platforms, supports and operating gear for oxygen 4 lances. For this reason, the movable roof section 27 does not extend across the full width of the furnace, so that said section does not interfere with the crane girder 32 and the other equipment and will act as a radiation shield when the movable door section 27 is open.

The two roof sections 21 and 27 slant generally upwardly from their back and front towards the hinge axis 28 of the movable roof section 27, as shown in FIGS. 1 and 4. The fixed roof section 21 comprises a bank of cooling pipes 35 (FIGS. 1 and 4) extending in parallel relationship along the section in the form of a panel. These cooling pipes 35 extend from the rear end of the furnace to a region beyond the vertical plane of the hinge axis 28 to underline at their front parts the rear part of the movable roof section 27. The tubes 35 are cooled by water or other suitable cooling fluid forced therethrough by a circulating pump (not shown). In a specific embodiment, the tubes 35 are cooled by boiling water at a pressure of 100 to 600 p.s.i.

To meet the requirements for a gas-tight furnace, the panel of tubes 35 is covered by a steel sheet 36 on the outside of said tubes, in contact with said tubes so as to attain a temperature closely approaching that of the cooling medium in the tubes, and is rigidly secured thereto in a manner to be described in connection with the cooling tubes on the movable roof section 27. This sheet 36 extends over substantially the entire area of the fixed roof section 21 and is protected from the direct radiation inside the furnace by the closely arranged tubes 35 and by a refractory layer 37 in which said tubes are embedded. The refractory layer 37 may be supported from the tubes 35 by studs (not shown) arranged in crossing relationship in the manner described in Patent No. 3,05 3,- 237 to lock the refractory layer to said tubes.

To reinforce the fixed roof section 21, there may be provided a plurality of channels 38 extending crosswise of the roof section and connected to the steel sheet 36 and a series of beams 40 along said roof section secured at their rear ends to a rear furnace wall structure 41 and connected at their other ends to the beam 25, which in turn is secured to the beams 14 forming part of the roof superstructure.

The movable roof section 27 comprises a series of cooling tubes 45 (FIGS. 1, 4 and 5), extending as a panel lengthwise of said section from the region where the series of cooling tubes 35 in the fixed roof section 21 terminate to the forward end of the movable roof section 27, as shown in FIG. 4, and cooled by a medium similar to that employed to cool the fixed tubes 35. To meet the requirements for a gas-tight furnace, the panel of tubes 45 is covered by a steel plate 46 on the outside of said tubes in contact with said tubes and extending over substantially the entire area of the movable roof section 27. This plate 46 is secured to the tubes 45 and for that purpose, the tubes may have rigid therewith U-shaped straps 47 (FIG. 11) passing through the plate and through beams 48 to be described, and wedges 50 passing through said straps and bearing against said straps and said plate. The steel plate 36 may be similarly connected to the tubes 35 in the fixed roof section 21.

The plate 46 is protected from direct radiation inside the furnace by the tubes 45 and by a refractory layer 51 in which said tubes are embedded and is maintained at a temperature close to that of the cooling fluid in the tubes by its face contact with said tubes. The refractory layer 51 may be supported from the tubes 45 by studs 52 (FIG. 11) secured to the tubes, the .studs from adjacent tubes 45 crossing each other to lock the refractory layer to the tubes in the manner described in the aforesaid patent. The refractory layer 37 is similarly supported from the tubes 35 in the fixed roof section 21.

To reinforce the movable roof section 27, there are provided the beams 43 (FIGS. 1, 2 and 11) in the form of channels extending crosswise of this roof section and affixed to the steel plate 46 in the manner described.

Extending along the top of the movable roof section 27 lengthwise thereof and rigid with the beams 48 are beams 54 and 55 interconnected at the ends by cross plates 56 and 57 (FIGS. 1, 2 and 4) to form a frame structure for the movable roof section. The tubes 45 carrying the refractory layer 51 are connected to the frame structure 54, 55, 56 and 57 through the reinforcing beams 48.

The hinge connection at 28 between the fixed roof section 21 and the movable roof section 27 comprises hollow hinge pins 58 (FIGS. 2, 3 and 4) journalled in bearings 59 held between brackets 60 and 61 secured to the frame plate 57 and to the frame structure 25, 26 of the fixed roof section 21. The forward end of the fixed roof section 21 extends forwardly beyond these hinge pins 58 in order to protect said pins and surrounding structure against the furnace heat, especially when the movable roof section 27 is open.

For circulating cooling liquid through the tubes 45 of the movable roof section 27, there is provided a pipe 62 journalled in the hinge pins 58 and divided by a partition 63 to form a supply header 64 and a return header 65 on opposite sides of said partition for the cooling liquid. The ends of the pipe 62 are connected to a fixed supply pipe 66 and a fixed return pipe 67 respectively by means of swivel couplings 68 with anti-friction bearings, permitting the pipe 62 to rock in the hinge pins 58 with the movable roof section 27 in its opening and closing movements.

The pipes 45 connect into the supply header 64 through metering orifice nipples 68a, and into the return header 65. The pipes 48 may be arranged in the form of U- shaped coils, nesting into each other, as shown in FIG. 5, and connecting at one end into the supply header 64 and at the other end into the return header 65.

The movable roof section 27 is flanked by fixed side roof sections 69 constituting forward extensions of the sides of the fixed roof section 21 respectively. The movable roof section 27 in closed position defines a juncture 70 (FIGS. 1, 2 and 4) between the rear end of this section and the fixed roof section 21, a juncture 71 between the front end of this movable roof section and the front furnace wall 17, and junctures 72 (FIGS. 1, 2 and 11) between the sides of the movable roof section and the fixed side roof sections 69 respectively. The structures in the regions of these junctures 70, 71 and 72 are such as to seal these junctures against the escape of air or gas therethrough into or out of the furnace, when the movable roof section 27 is closed.

For sealing the juncture 70 (FIG. 4) between the front end of the fixed roof section 21 and the rear end of the movable roof section 27, the series of cooling tubes in this fixed roof section includes a tube 35a and a bank of tubes 35b extending in parallel relationship along the front end of the fixed roof section 21. The bank of tubes 35 forms a panel extending over substan tially the entire area of the fixed roof section 21, and the bank of tubes 35b, except for the bottom tube a, extends upwardly in a single plane from said bank of tubes 35 with a slight forward inclination, with said bottom tube a extending forwardly of said plane to provide an offset in the bottom of the juncture 70 and the tube 35a and the top tube b in the bank of tubes 35!) are in a plane extending upwardly and rearwardly to define conjointly a seat for a series of sealing blocks 75 to be described. The steel plate 36 extends along the bottom panel of tubes 35 and also slantingly upwardly along the bank of tubes 35b contiguous thereto and then upwardly and rearwardly underneath the tube 35a, and although the tubes 35 are entirely embedded in the refractory layer 37, the tubes 35b are only partially embedded in the refractory layer, to expose the forward sides of these tubes 35b facing the juncture 70.

The construction described defines the stationary side of the juncture 70 constituting the front end of the fixed roof section 21.

To form the movable side of the juncture 70 constituting the rear end of the movable roof section 27, the series of cooling tubes in this roof section comprises a bank of tubes 45a extending in parallel relationship near the rear end of the movable roof section 27 and connected to the supply header 64 and the return header 65, in a manner described in connection with the tubes 45. The bank of tubes 45 forms a bottom. panel extending throughout substantially the entire area of the movable roof section 27, and the bank of tubes 4511, except for the bottom tube (2, slopes upwardly and forwardly from the rear end of said bank of tubes 45. This bottom tube c projects forwardly of the rest of the bank of tubes 45a and is opposite to and substantially on the same level as the bottom tube a in the bank of tubes 35b, to provide with said bottom tube a an offset in the bottom of the juncture 70, serving the purpose to be described. The bank of tubes 45a above the bottom tube c, shown in FIG. 4 constituting four tubes in a single plane, extends upwardly with a slight forward inclination. and is parallel and contiguous to the bank of tubes 35b above the tube a of the latter bank, in closed position of the movable roof section 27. The upper section of the bank of tubes 45a shown constituting three tubes, projects upwardly and forwardly beyond the top level of the bank of tubes 35b and veers from the lower section of the bank of tubes 45a with an increased forward slant in relation to the lower section of the bank of tubes 45a to define conjointly an inclined seat for the series of sealing blocks 75 along which the blocks can slide into seating contact with the tube 35a and the top tube b in the bank of tubes 35!), as the movable roof section 27 is moved from open position into closed position, as will be described more fully.

The steel plate 46 extends along the bottom panel of tubes 45 and also slantingly upwardly along the bank of tubes 45a contiguous thereto, and although the tubes 45 are entirely embedded in the refractory layer 51, the bank of tubes 45a are only partially embedded in the refractory layer, so that the sides of these tubes 45a confronting the bank of tubes 3512 are exposed.

The upper sections of the series of cooling tubes on opposite sides of the juncture 70 form a V pocket in which the sealing blocks 75 nest in closed position of the movable roof section 27.

The construction described defines the movable side of the juncture 70 constituting the rear end of the movable roof section 27.

The sealing blocks 75 are arranged in alignment in a row over the juncture 70 and are desirably made of steel, as for example, of hot rolled carbon steel for direct contact with the tube 35a, the top tube b of the bank of tubes 35]) and the tubes in the upper section of the bank of tubes 45a. All of the cooling tubes in the furnace are desirably of steel, and especially the tubes which come in contact with the sealing blocks 75, to assure effective sealing contact between these blocks and the latter contacting tubes without being marred or otherwise damaged.

The sealing blocks 75 are carried by the framework of the movable roof section 27 in such a manner that two adjoining faces of each block are in contact with the upper tubes on the two roof sections 21 and 27 in the region of the juncture 70 in closed position of the movable roof section 27. For that purpose, the sealing blocks 75 are so supported from the framework of the movable roof section 27 by pivotal-lost motion connections that they float and move automatically under the action of gravity rotationally and translationally into sealing contact with the upper tubes on the two roof sections 21 and 27 in the regions of the juncture 70, regardless of any misalignment between the two roof sections 21 and 27 in closed position of the roof section 27. For so supporting the sealing blocks 75 from the frame structure of the movable roof section 27, there is provided a structural member 80 (FIGS. 4 and 6) shown in the form of an angle iron above the juncture 70 aifixed to the underside of the beams 55 and extending along said juncture. The sealing blocks 75 are of substantially rectangular oblong cross-section, and each one at the top has secured thereto a U-shaped staple 81 tapering towards its bend end and loosely interlocked with a U-shaped staple 82 secured to the structural member 80. The sealing blocks 75 extend end to end in close proximity to each other with just suflicient clearance therebetween to permit free independent movement of these blocks in relation to the frame structure of the movable roof section 27, and due to gravity action, rest at all times in inclined position on the tubes at the upper sections of the bank of tubes 45a with one side face in direct contact with the tubes at said upper section, when the roof section 27 is clos d or partially open. The inclination of the upper veering section of the bank of tubes 45a is such in relation to the coefficient of friction between the sealing blocks 75 and the tubes in said upper section, as to cause the sealing blocks to slide down along said tubes in said upper section under the action of gravity, as the movable roof section 27 is lifted, until the blocks are suspended from the staples 82 while resting against the tubes in said upper section.

As the movable roof section 27 is closed, the lower ends of the sealing blocks 75 seat on the fixed tube a and the fixed upper tube b of the bank of tubes 35b, while the sealing blocks are being supported against the upper section of the bank of tubes a, and the sealing blocks while in this position slide upwardly along said upper section of the tube bank, until the movable roof section has been lowered into fully closed position, as shown in FIG. 4. It is seen that regardless of any misalignment between the two roof sections 21 and 27 in closed position of the roof section 27, the sealing blocks 75 will automatically adjust themselves independently of each other so as to extend in direct contact with the tubes on both sides of the juncture 70, thereby sealing off said juncture against flow of air into the furnace or escape of hot gases therefrom.

The cooling tubes on opposite sides of the juncture come into contact with each other or almost come into contact with each other, and since the number of tubes confronting each other on opposite sides of the juncture is substantial, it is seen that although these tubes in the absence of the sealing blocks may not seal the juncture against flow of air or gas therethrough, they block to a substantial extent direct radiation from the furnace to the sealing blocks 75. Also, because the bottom tubes a and c in the bank of tubes 35b and the bank of tubes 45a are offset in relation to the rest of said banks of tubes, the juncture 70 is winding or devious, thereby further protecting the sealing blocks against direct radiation from the furnace. For these reasons, the sealing blocks will not overheat and consequently can be made of ordinary hot rolled carbon steel.

The juncture 71 (FIGS. 1 and 4) between the front end of the movable roof section 27 and the front furnace wall 17 is sealed by sealing blocks 84. For that purpose, the series of tubes in the movable roof section 27 comprises an inclined planar bank of tubes 45b inclined upwardly and forwardly in closed position of said roof section. This bank of tubes 45b is on one side of the juncture 71 and consists of horizontal tubes extending along the forward end of the movable roof section 27 and connected to the supply header 64 and the return header 65 in the manner described in connection with the tubes 45.

The steel plate 46 extending along the bottom panel of tubes 4-5 also extends slantingly upwardly along the bank of tubes 45b in contact therewith, and the latter tubes are only partially embedded in the refractory layer 51, so that the forward sides of these tubes facing the juncture 71 are exposed.

The construction described defines the movable side of the juncture 71 constituting the front end of the movable roof section 27.

To form the fixed side of the juncture 71, cooling tubes in the furnace wall 17 connected to a fixed supply header 86 and to a fixed return header (not shown), form a planar bank inclined upwardly and forwardly parallel to the bank of tubes 45b, the tubes extending horizontally along the juncture 71. A series of cooling tubes 87 from the furnace wall 17 extend across the bottom of the bank of tubes 45]) to make the juncture 71 winding and to shield thereby the sealing blocks 84 against direct heat radiation from the hearth of the furnace.

A steel plate 88 extends from the furnace wall 17 along the bank of cooling tubes 87 and 85 in contact therewith to serve as a gas seal, as in the case of the plates 36 and 46. Refractory material from the furnace wall 17 does not completely encompass th tubes 85, so that the sides of said tubes confronting the tubes 45]) are exposed.

The construction described defines the fixed side of the juncture 71.

The sealing blocks 84 desirably made of steel, as for example, of hot-rolled carbon steel, are arranged in alignment in a row over the juncture 71 for direct contact with the top tube d of the bank of tubes 45b also made of steel, and with the upper section of the bank of tubes 85, also made of steel. The bank of tubes 85 extends upwardly beyond the top tube 0! in the bank of tubes 4512 when the movable roof section 27 is in closed position. These sealing blocks 84 are carried from the framework of the movble roof section 27 in such a manner, that in closed position of the movable roof section 27, two adjoining faces of each block are in contact with the top tube d of the bank of tubes 45b on the movable roof section and with the upper sections of the fixed bank of tubes 85 supported on the front furnace wall 17. For that purpose, the sealing blocks 84 are so supported from the framework of the movable roof section 27, by pivotal-lost motion connections, that they float and move automatically under the action of gravity rotationally and translationally into sealing contact with the upper tubes of the banks. of tubes 45b and 85, regardless of any misalignment between the movable roof section 27 and the furnace wall 17, in closed position of the movable roof section 27. For so supporting the sealing blocks 84 from the frame structure of the movable roof section 27, there is provided a structural member 91 in the form of an angle iron, afiixed to the frame plate 56 and extending along the juncture 71. The sealing blocks 84 are of substantially rectangular oblong cross-section, except that the lower ends 92 of these blocks are bevelled to assure the retention of these lower ends in proper sealing position between the upper tubes of the two banks of tubes 45b and 85 in closed position of the movable roof section 27 and to cause these blocks to slide by the action of gravity along the top tube d of the bank of tubes 45b into engagement with the upper section of the bank of tubes 85, in closed position of the movable roof section 27, as shown in FIG. 4. Each one of the sealing blocks 84 has secured to the top a staple 93 caught by a corresponding hook 94 affixed to the structural member 91. The sealing blocks 84 extend end to end in close proximity to each other with just sufiicient clearance therebetween to permit free independent movements of these blocks in relation to the frame structure of the movable roof section 27. Due to gravity action, the sealing blocks 84 rest at all times on the top tube a of the bank of tubes 45b on the movable roof section 27, whether this roof section is open or closed. For that purpose, the center of gravity of the sealing block 84 is in a vertical plane, which is never to the left of the vertical plane of the axis of pivot support of the block, regardless of the angular position of the movable roof section 27, so that the block is always gravitationally urged clockwise (FIG. 4)

9 about its pivot support into engagement with the top tube d of the bank of tubes 45b.

In a specific embodiment of the invention, the angle between the plane of the tubes 85 and a horizontal plane is equal to or greater than 45, and the face of the sealing block 84 in contact therewith has a corresponding angle with the horizontal. This assures movement of the block 84 in contact with both the top tube d in the bank of tubes 45!) and the upper section of the bank of tubes 85 in closed position of the movable roof section 27, regardless of distortion.

The angle of the bevel end 92 of the sealing block 84 is sufficiently steep tocause the block to abut the top tube a of the bank of tubes 45b, and also to cause the block to slide slantingly downwardly and outwardly along said top tube, as the movable roof section 27 is moved angularly into open position away from the fixed bank of tubes 85, until the bend in the staple 93 engages the bend in the hook 94. In this limiting position of the sealing block 84, the bevelled end 92 of the sealing block 84 still seats on the top tube d of the bank of tubes 45b.

Due to their pivotal supports, the sealing blocks 84 tend to rotate clockwise (FIG. 4) about their pivotal axis provided by the hook 94 but are prevented from doing so because of the engagement of the bevelled lower ends of these blocks with the top tube d in the bank of tubes 45b, even though the movable roof section 27 may be in raised position; in this raised position of the roof section 27, these blocks 84 are out of engagement with the upper section of the bank of fixed tubes 85. As the movable roof section 27 moves into closed position, the sealing blocks 84 move alongside of the upper section of the fixed bank of tubes 85 and slide therealong until said movable roof section has reached a fully closed position as shown in FIG. 4, in which position, the blocks are in contact not only with the top tube (1 in the bank of tubes 4512 but with a number of tubes in the upper section of the bank of tubes 85. The face of each sealing block 84 which comes into contact with the upper section of the bank of tubes 85 has a bevel 95 at its lower section to ease entry of the sealing block into engagement with the upper section of the bank of tubes 85, as the movable roof section 27 closes. The shape of the sealing block 84, the location of its center of gravity with respect to its pivotal axis, the inclination of its bevelled end 92 and the coefficient of friction between said bevelled end and the top tube (1 of the bank of tubes 45b are so correlated, as to maintain the sealing block seated on said tube at all times and to cause said block to slide forwardly along said top tube in closed position of the movable roof section 27, if the upper section of the bank of tubes 84 were not present. This assures movement of the sealing blocks 84 into position to seal the juncture 71 against the flow of air into the furnace or escape of hot gases therefrom. The floating support of the blocks 84 described, causes these blocks to automatically assume sealing positions across the juncture 71 irrespective of any misalignment between the movable roof section 27 and the front furnace wall 17 in closed position of said roof section.

To provide sealing means for the side junctures 72, the reinforcing channel beams 48 on the movable roof section 27 have sections 48:: (FIG. 11) near their ends on the sides of said roof section slanting upwardly and outwardly in closed position of said roof section, and end sections 48b extending substantially vertically in closed position of said roof section. The main panel of tubes 45 continues along the sides of the movable roof section 27 slantingly upwardly and outwardly to form on each side a slanting bank to tubes 45c (FIGS. 4, 7, 8 and 11) defining the movable side of the corresponding juncture 72. The bank of tubes 45c consists of tubes extending parallel along the juncture 72 and connected to the supply header 64 and the return header 65, as in the case of the tubes 45. Each side section of the steel plate 46 extends along the back of the corresponding slanting bank of tubes 450 between the bank of tubes and the reinforcing channel beam sections 48a and 48b. The steel plate 46 is bent upwardly along its outer side margins and the top tube 2 in each bank of tubes c veers slightly upwardly, for the purpose to be made apparent.

The refractory layer 46 embedding the main panel of tubes 45 is continued along the lower section of the slanting bank of tubes 45c to full thickness and is reduced in thickness along the upper section of the bank of tubes 45c, so that the outer sides of the tubes in this upper section are exposed.

The construction described in connection with each juncture 72 defines the movable side of said juncture.

To form the fixed side of each juncture 72, each of the fixed side roof sections 69 comprises a series of cooling tubes 100 (FIGS. 7, 8 and 11) forming a panel over said fixed roof section and continuing slantingly and outwardly to form a bank of tubes 100a extending substantially parallel along the corresponding juncture 72. Each bank of tubes 100a extends in a fiat plane substantially parallel to the plane of the section of the slanting bank of tubes 45c below the veering upper tube e of the latter bank, so that the upper sections of the two banks of tubes 45c and 100a conjointly form a V-pocket 103 therebetween to receive the lower bevelled ends of sealing blocks 104 to be described. The tops of the two banks of tubes 45c and 100a are approximately at the same horizontal level in normal closed position of the movable roof section 27 when said roof section is free from distortion, as shown in FIG. 11.

The tubes 100 and 100a are secured to a steel plate 105 and to a series of channel beams 106 by strap and wedge means 107 similar to the strap and wedge means 47, employed in connection with the tubes 45, plate 46 and reinforcing beams 48. The steel plate 105 extends over substantially the entire area of the corresponding fixed side roof section 69 to serve as a gas seal, and tubes and 100a are embedded in a layer 108 of refractory interlocked with said tubes by means of cross studs (not shown) secured to the tubes in the manner shown in the aforesaid patent. The plate extends along the bank of the tubes 100 and 100a in conformity with the curvature followed by the tubes and the reinforcing channel beams 106 have corresponding curvature.

The refractory layer 108 is of full thickness to completely encompass the tubes 100 and the lower part of the bank of tubes 100a but at the upper section, it is reduced in thickness to expose the sides of the tubes 100a confronting the tubes 45c.

The construction described in connection with each juncture 72 defines the fixed side of said juncture.

It should be noted that the juncture 72 in closed position of the movable roof section 27 has an entrance passage 72a of restricted width extending upwardly with slight outward inclination and bounded by refractory walls 51 and 108, and a passage 72b bounded by two contiguous banks of tubes 45c and 100a and shifting direction for inclination upwardly and outwardly at a lesser angle with the horizontal, so that the juncture 72 is somewhat winding or devious, impeding thereby direct passage of air or gas through said juncture, and shielding the sealing blocks 104 against direct radiation from the furnace hearth, permitting thereby the sealing blocks to be made of hot rolled carbon steel. The tubes 45c and 100a and especially those coming in contact with the sealing blocks are also of steel.

The sealing blocks 104 for each side juncture 72 comprises a row of aligned blocks close together with enough clearance therebetween to permit independent movements of said blocks laterally of the direction of the row. The sealing blocks 104 are independently supported from the frame structure of the movable roof section 27 by pivotal-lost motion connections, and in the manner to cause said blocks to float and move rotationally and transslationally to assume sealing positions automatically under the action of. gravity, irrespective of any misalignments between the sides of the movable roof section 27 and the fixed side roof section 69. For that purpose, there is secured to the upper ends 41% of the reinforcing beams 48 on each side of the movable roof section 2.7 a structural member 111 shown in the form of an angle iron, extending over and along the corresponding juncture 72 and presenting a web 112 slanting downwardly and outwardly. Secured to this web 112 are a series of pins 113, one for each sealing block 104, terminating in an up wardly offset end section 114 serving as a head for said pin. Each of the sealing blocks 104 has secured to a corner 115 thereof near one end of the block a staple 116 with legs 117 and 118, converging towards a bend 121 inter connecting said legs. The pins 113 pass freely through respective staples 116 and are long enough to permit the blocks 104 connected to these staples (1) to move up and down freely in a plane parallel to the inclined plane of the web 112, (2) to swing about said pins in planes parallel to said web and (3) to swing to a limited extent about horizontal axis at right angles to the pins and passing therethrough, so that said blocks will accommodate themselves automatically to sealing position, while the offset heads 114 on said pins prevent the staples from being withdrawn from said pins. In other words, the connection between the blocks 104 and the structural member 111 is a universal one within limits sufliciently wide to permit adjustments to meet any of the conditions of misalignment encountered.

The sealing blocks 1134 may slant downwardly from the hinge pins 58 of the movable roof section 27 due to the slant in the roof section in closed position, as shown in FIG. 4. In order to maintain the sealing blocks 104 in proper relationship in this inclined position, the staple 116 on each block is so positioned and so located in relation to the corresponding pin 113 extending therethrough, that the leg 117 of said staple engages said pin and holds the block against sliding movement down hill towards the free end of the movable roof section, as shown in FIG. 4.

To assure against jamming of the staples 116 against the pins 113 as the movable roof section 27 is lowered into closed position, the leg 117 of each staple 116 extends 95 with respect to the radius line C from the axis of the hinge pins 58 to the corresponding pin 113, as shown in FIG. 4. This permits the staple leg 117 to ride with ease upwardly along the pin 113, as the movable roof section 27 is lowered into sealing position, and thereby permits the corresponding sealing block 184 to assume its proper sealing position. A slight jamming between the, staple 116 and the pin 113, as the movable roof section 27 is opened, is not of any consequence.

Also, to assure that the sealing blocks 1M hang properly when the movable roof section 27 is raised, the blocks are designed and arranged in relation to the pins 113 and the staples 116, as to cause the center of gravity of each block to lie in the vertical plane of the axis of the corresponding supporting pin 113, as the bend 12d of the corresponding staple engages said pin.

The sealing blocks 11% are of substantially oblong rectangular cross-section except that the lower end 122 of each block is bevelled so that the block is somewhat wedge-shape and tapers to a thin edge 123 and one adjoining side 124 of the block is slightly bevelled or chamfered near said end to permit smooth entry of the lower section of each sealing block into sealing engagement with the upper tubes of the bank of tubes 119011 as the movable roof section 27 is being moved into closed position from an elevated position.

In closed position of the movable roof section 27, the sealing blocks 1% will be inclined upwardly and outwardly as shown in FIG. 11 with the bevelled end 122 in seating engagement with the top tube e in the bank of tubes 45c and with the side 124 of the block in seating engagement with the upper tubes in the bank of tubes 1110a. The location of the center of gravity of each sealing block 104, its weight, the direction of the plane of the web 112 determining the approximate plane of guidance of the sealing block in its up and down movements relative to the movable roof section 27, the direction of inclination of the block in relation to this guiding plane and the coefficient of friction between the block and the upper tube 2 of the bank of tubes 450 are so correlated, that the sealing block will automatically slide along said upper tube into sealing contact with the upper section of the bank of tubes 196:! in closed position of the movable roof section 27, regardless of any misalignment between the sides of said roof section and the fixed side roof sections 69.

In elevated open position of the movable door section 27, the bend 129 in the staple 116 of each sealing block 1114 is resting on the corresponding pin 113, so that the block is suspended therefrom. In this limiting position of the sealing block 1114, the bevelled end 122 of the block is seated on the top tube 0 of the bank of tubes 450 with the block spaced from the bank of tubes 160a, and the center of gravity of the block is in the vertical plane of the axis of the supporting pin 113. As the movable roof section 27 is moved downwardly into closed position, the face 124 of the sealing block 164 first makes contact with the top tube of the bank of tubes 1011a and thus establishes a gas seal before the roof section is fully closed. As the movable roof section 2'7 continues to close, the sealing block 104 will tend to rest on the top tube of the bank of tubes 1011a and lose contact with the top tube e of the bank of tubes 45c. However, the inclination of the bank of tubes 1119a is steep enough to cause the sealing block 1134 to slide along the upper sections of the bank of tubes 1111141, until the bevelled end 122 of the sealing block is in engagement with the top tube e in the bank of tubes 45c. In a specific form of the invention, the inclination of the bank of tubes a is equal to or greater than 45 with the horizontal, to assure contact of the sealing block 1114 with the upper tubes of the two banks of tubes 45c and 1110a, in closed position of the movable roof section 27.

FIGS. 11, and 13 to 17 show different conditions of alignment encountered with the movable roof section 27 completely closed, and show the sealing blocks 1114 accommodating themselves to these different conditions. FIG. 11, for example, shows the normal position of the movable roof section 27 with respect to the fixed roof section 21, when there is not distortion or misalignment. FIG. 13 shows the structure of FIG. 11 but in a different position of the movable roof section 27 in connection with an orientation diagram. In the position shown in FIG. 13, the movable roof section 27 in fully closed position has been displaced from a normal index point N corresponding to the positon of said roof section 27 shown in FIG. 11, upwardly and to the left to a distortion point D; in the position shown in FIG. 14, the movable roof section 27 in fully closed position has been displaced from a normal index point N directly upwardly to a distortion point D; in the position shown in FIG. 15, the movable roof section 27 in fully closed position has been displaced from a normal index point N directly to the left to a distortion point D; in the position shown in FIG. 16, the movable roof section 27 in fully closed position has been displaced from a normal index point N, upwardly and to the right to a distortion point D; and in the position shown in FIG. 17, the movable roof section 27 in fully closed position has been displaced from a normal index point N, downwardiy and to the left to a distortion point D. It is seen that in all of the different conditions of alignment or misalignment encountered, the sealing blocks 1% in every case, have moved into position to seal off the exit side of the juncture 72.

The junctures 711, 71 and '72 are arranged in rectangular relationship, and the sealing blocks 75, 84 and 104 are similarly arranged over these junctures. At each corner of this rectangular lineup of sealing blocks, it is desirable to provide some means for closing the joints where the two end blocks from adjoining rows of blocks come together, while permitting these two blocks to move rela tively to a limited extent sufiiciently to seat into sealing position upon closing of the movable roof section 27. As shown in FIGS. 6, 9 and 10, one of the blocks at each corner has a cut-out or recess into which the adjoining block at said corner slidably nests. In the specific form shown, each row of blocks 104 has end blocks 104a and 1041) similar to the blocks 104, except that block 104a has a recess 130 for receiving the end section of a block at the end of the adjoining row of blocks 75 and block has a recess 131 for receiving the end section of a block at the end of the adjoining row of blocks 84. The block 104a shown in FIGS. 6 and 9 has its lower end 122a corresponding to the lower end 122 of the blocks 104 bevelled, and its adjoining side 124a corresponding to the side 124 of the blocks 104 also slightly bevelled. The recess 130 in the block 104a has one side 133 in a vertical plane and in position to cause the vertical end of a block at the end of the row of blocks 75 to extend into said recess into close proximity, if not into actual contact with said recess side when the movable roof section 27 is in closed position, and has an adjoining side 134 slanted to correspond to the slant of the blocks 75 and in position to cause the end section of said end block 75 to extend close to if not to actually conformably seat on said recess side 134 when the movable roof section 27 is in closed position.

The recess 131 in the block 104]) has one side 135 in a vertical plane and in position to cause the vertical end of a block at the end of the row of blocks 84 to extend into said recess into close proximity, if not into actual contact with said recess side when the movable roof section 27 is in closed position, and has an adjoining side 136 slanted to correspond to the slant of the blocks 84 and in position to cause the end section of said end block 84 to extend close to if not to actually conformably seat on said recess side 136 when the movable roof section 27 is in closed position.

With the construction of the present invention, the charging capacity of the furnace is greatly increased, since both the front doorways 18 and the top doorways 22, can be used separately or at the same time, thereby cutting down materially on the timed consumed for these operations.

The invention has been described in connection with an open hearth furnace, in which the sections 10 shown in FIG. 2 can be multiplied side by side, with each section having a front door and a roof door as described. However, as far as certain aspects of the invention are concerned, the furnace may be of any type, in which it is desired to seal the furnace against the escape of gas or the infiltration of air therein, and in which the use of a roof door is useful.

While the invention has been described with particular reference to a specific embodiment, it is to be understood that it is not to be limited thereto but is to be construed broadly and restricted solely by the scope of the appended claims.

What is claimed is:

1. In a furnace, the combination comprising a roof having a pair of sections, one of which is movable, hinge means supporting said movable roof section for pivotal movement relative to the other roof section, said movable section defining with said other section a doorway and constituting a door for said doorway, said sections defining therebetween a juncture in closed position of said movable door section, tubes for carrying heat exchange liquid lining opposite sides of said juncture, and sealing means carried by said movable door section for adjusting gravitational movement relative to said movable door section into sealing position between the tubes on opposite sides of said juncture automatically upon the closing of said movable door section, to seal said juncture.

2. In a furnace, the combination comprising a roof with a fixed section and a hinged movable section defining with said fixed section a doorway and constituting a door for said doorway, hinge means supporting said movable roof section, said sections defining therebetween a juncture in closed position of said movable door section, a series of cooling tubes carried by said movable door section and extendingover said movable door section to form a panel thereover and continuing upwardly as a bank along one side of said juncture, a fixed series of cooling tubes on said fixed section including a bank of' cooling tubes continuing upwardly along the other side of said juncture, a plurality of sealing members extending in a row along said juncture, and means supporting said sealing members on said movable door section for adjusting gravitational movements relative to each other and relative to said movable door section into juncture sealing positions between and in contact with tubes on both banks automatically as said movable door section is moved into closed position.

3. In a furnace, the combination comprising a roof with a fixed section and a movable section defining with said fixed section a doorway and constituting a door for said doorway, hinge means supporting said movable roof section for rocking rotatable movement about a hinge axis said sections defining therebetween a juncture in closed position of said movable door section, a first series of cooling tubes carried by said movable door section and extending over said movable door section to form a panel thereover and continuing upwardly as a bank along one side of said juncture, a supply header for said series of pipes centered on the hinge axis. and journalled for rocking rotatable movement about said axis with said movable door section, a return header for said series of pipes centered on said hinge axis and journalled for rocking rotatable movement about said axis with said movable door section, a fixed second series of cooling tubes on said fixed section including a bank of cooling tubes continuing upwardly along the other side of said juncture, a plurality of sealing members extending in a row along said juncture, and means supporting said sealing members on one of said roof sections for adjusting gravitational movements relative to each other and relative to the latter section into juncture sealing positions automatically as said movable door section is moved into closed position.

4. In a furnace, the combination comprising a roof with a fixed section and a substantially rectangular movable section defining with said fixed section a doorway and constituting a door for said doorway, hinge means supporting said movable roof section, said sections defining therebetween a juncture on each side of said movable door section in closed position of said movable door section, said junctures being substantially rectangularly arranged around all sides of the movable door section, and means for sealing each juncture against the flow of gas therethrough, comprising a plurality of sealing members extending in a row along each juncture, and means supporting said sealing members on one of said roof sections for adjusting gravitational movements relative to each other and relative to the latter section into juncture sealing positions automatically as said movable door section is moved into closed position.

5. In a furnace, the combination comprising a roof with a fixed section and a movable section defining with said fixed section a doorway and constituting a door for said doorway, hinge means supporting said movable door section, said sections defining therebetween a juncture in closed position of said movable section, two banks of heat exchange tubes lining both sides of said juncture with the tubes running along the length of the juncture in closed position of the movable door section, the two banks of tubes being carried by said roof sections respectively and one of said banks being inclined with respect to the horizontal in closed position of the movable roof section, and means for sealing said juncture against the flow of gas therethrough, comprising a plurality of sealing blocks extending in a row along said juncture, and means supporting said sealing blocks on said movable door section for movements relative to each other and relative to the movable door section into juncture sealing positions automatically as said movable door section is moved into closed position, said supporting means having means causing said sealing blocks to seat on an upper tube of the other bank and to lie in an inclined position on the upper tubes of the inclined bank in closed position of said movable door section.

6. In a furnace, the combination as described in claim 5, wherein said supporting means comprise a lost-motion connection for each of said sealing blocks permitting said sealing blocks to slide along the upper tubes of the inclined bank, and wherein the upper tubes on the inclined bank are so steeply inclined as to cause the sealing blocks to slide under the action of gravity downwardly along the upper tubes of said inclined bank and into contact with the upper tube of said other bank as said movable door section moves into closed position.

7. In a furnace, the combination as described in claim 5, wherein said supporting means comprise a lost-motion connection for each of said sealing blocks permitting said sealing blocks to slide along the upper tubes of the inclined bank, said connection having a pivot axis transverse to the direction of slide movement of said sealing block, and wherein the upper tubes on the inclined bank are so steeply inclined as to cause the sealing blocks to slide under the action of gravity downwardly along the upper tubes of said inclined bank and into contact with the upper tube of said other bank as said movable door section moves into closed position, and wherein said supporting means are spaced from the centers of gravity of the sealing blocks to cause said blocks to turn about their corresponding pivot axes and to hang by the action of gravity into contact with the upper tube of said other bank, as said movable door section is moved into open position.

8. In a furnace, the combination as described in claim 5, said inclined bank of tubes being carried by the movable door section while said other bank of tubes is fixed, said sealing blocks resting on the upper tubes of said inclined bank in inclined positions at all times, whether the movable door section is open or closed, said supporting means comprising a lost-motion connection for each of said sealing blocks permitting said sealing blocks to move translationally along the upper tubes of said inclined bank, the upper tubes of said inclined bank being so steeply inclined as to cause the sealing blocks to slide under the action of gravity downwardly along the upper tubes of said inclined bank and into contact with the upper tube of said other bank as said movable door section moves into closed position.

9. In a furnace, the combination as described in claim 5, said bank of inclined tubes being carried by the fixed roof section while the other bank of tubes is carried by said movable roof section, said sealing blocks resting on the upper tubes of said inclined bank when said movable roof section is in closed position, said supporting means comprising a lost-motion connection for each of said sealing blocks permitting said sealing blocks to slide translationally along the upper tubes of said inclined bank, and said inclined bank being so steeply inclined as to cause the sealing blocks to slide under the action of gravity downwardly along the upper tubes of said inclined bank and into contact with the upper tube of said other bank as said movable door section moves into closed position.

10. In a furnace, the combination as described in claim 9, wherein said supporting means are spaced from the centers of gravity of the sealing blocks to cause said blocks to hang into contact with the upper tube of said other bank, as said movable door section is moved into open position.

llll. In a furnace, the combination comprising a roof with a fixed section and a movable section defining with said fixed section a doorway and constituting a door for said doorway, hinge means supporting said movable door section, said sections defining therebetween a juncture in closed position of said movable section, the structure of said juncture presenting a pair of seats on opposite sides of said juncture, one of which is inclined with respect to the horizontal, one of said seats being fixed, the other seat being carried by said movable door section, and means for sealing said juncture against the flow of gas therethrough, comprising a plurality of sealing blocks extending in a row along said juncture and means supporting said sealing blocks on said movable door section for movements relative to each other and relative to the movable door section into juncture sealing positions and automatically as said movable door section is moved into closed position, said supporting means having a combined pivot and lost-motion connection for each of said sealing blocks causing said sealing blocks under the action of gravity to swing into seating engagement with said inclined seat and to slide along said inclined seat, said inclined seat being steep enough to cause the blocks to slide therealong under the action of gravity into contact with the other seat as the movable door section moves into closed position.

12. In a furnace, the combination as described in claim 11, wherein said supporting means are spaced from the centers of gravity of the sealing blocks to cause said blocks to hang into contact with the seat fixed to said movable door section, as said movable door section is moved into open position.

13. In a open hearth furnace for making steel, the combination comprising a roof with a fixed section and a hinged movable section defining with said fixed section a doorway and constituting a door for said doorway, hinge means supporting said movable roof section, said sections defining therebetween junctures extending around all sides of said movable roof section, the axis of the hinge for said movable roof section extending longitudinally of the furnace and being located intermediate of the rear and front of the furnace, whereby said fixed roof section has substantial width between the rear of the furnace and said hinge axis, a crane girder over said fixed roof section extending along the furnace between the vertical plane of the rear of the furnace and the vertical plane of said hinge axis, means for movinig said movable roof section substantially in upright open position in front of said crane girder, said movable roof section in said upright open position extending between said doorway and said crane girder to shield said crane girder against radiation heat from the interior of the furnace, and means for sealing said junctures automatically as said movable roof section is moved into closed position comprising a plurality of sealing members extending in a row along said juncutre, and means supporting said sealing members on one of said roof sections for adjusting movements relative to each other and relative to the latter section into juncture sealing positions automatically due to the force of gravity on said sealing members as said movable roof section is moved into closed position.

14. In an open hearth furnace for making steel, the combination comprising a roof with a fixed section and a movable section defining with said fixed section a doorway and constituting a door for said doorway, hinge means supporting said movable roof section for pivotal movement relative to the other roof section, said sections defining therebetween junctures extending around all sides of said movable door section, and means for automatically sealing said junctures against the flow of gas therethrough as said movable door section is closed, irrespective of any misalignment between said movable door section and said fixed section comprising a plurality of sealing members extending in a row along said juncture, and means supporting said sealing members on one of said roof sections of rotational and translational adjusting movements under the action of gravity relative to each other and relative to the latter roof section into juncture sealing position automatically as said movable door section is moved into closed position.

15. In an open hearth furnace for making steel, the combination comprising a roof with a fixed section and a movable section defining with said fixed section a doorway and constituting a door for said doorway, hinge means supporting said movable roof section for pivotal movement relative to the other roof section, each of said roof sections comprising a series of cooling tubes for carrying a cooling medium, said tubes being arranged in a form of a panel extending over the area of said roof section, a steel plate extending over said series of tubes on the outer side thereof and in contact therewith, and a layer of refractory material covering said tubes and extending from said plate, said roof sections defining therebetween junctures extending around all sides of movable door section, and said series of tubes extending to the sides of said junctures for lining said junctures, and means for automatically sealing said junctures against the flow of gas therethrough as said movable door section is closed, irrespective of any misalignment between said movable door section and said fixed section comprising a plurality of sealing members extending in a row along said juncture, and means supporting said sealing members on one of said roof sections for adjusting gravitational movements relative to each other and relative to the latter section into juncture sealing positions automatically as said movable door section is moved into closed position.

16. In a furnace, the combination comprising a roof having a pair of sections, one of which is movable, hinge means supporting said movable roof section for pivotal movement relative to the other roof section, said movable section defining with said other section a doorway and constituting a door for said doorway, said sections defining therebetween a juncture in closed position of said movable door section, heat exchange tubes lining said juncture, and means for sealing said juncture against the flow of gas therethrough, comprising a plurality of sealing members extending in a row along said juncture, and means supporting said sealing members on one of said roof sections for adjusting gravitational movements relative to each other and relative to the latter section into juncture sealing positions automatically as said movable door section is moved into closed position, said supporting means also supporting said sealing members for movements into contact With some of said tubes in said juncture sealing positions.

17. In a furnace, the combination, comprising a roof having a pair of sections, one of which is movable, hinge means supporting said movable roof section for pivotal movement relative to the other roof section, said movable section defining with said other section a doorway and constituting a door for said doorway, said sections defining therebetween a juncture in closed position of said movable door section, two banks of heat exchange tubes lining both sides of said juncture and carried by said sections respectively, and said means for sealing said juncture against the flow of gas therethrough, comprising a plurality of sealing members extending in a row along said juncture and between said banks of tubes in closed position of said movable door section, and means supporting said sealing members on one of said roof sections for adjusting gravitational movements relative to each other and relative to the latter section automatically as said movable door section is moved into closed position, said supporting means also supporting said sealing members for movements into sealing contact with tubes in both banks in said juncture sealing positions.

18. In a furnace, the combination comprising a roof having a pair of sections, one of which is movable, hinge means supporting said movable roof section for pivotal movement relative to the other roof section, said movable section defining with said other section a doorway and constituting a door for said doorway, said sections having a structure defining therebetween a juncture in closed position of said movable door section, and means for sealing said juncture against the flow of gas therethrough, comprising a plurality of sealing members in the form of metal blocks extending in a row along said juncture and adapted to seat on the upper sides of said juncture in closed position of said movable door section, the structure defining said juncture being winding in a direction transverse to the length of the juncture to prevent direct radiation of heat from the interior of the furnace to the blocks and thereby to prevent overheating of said blocks, and means supporting said sealing blocks on one of said roof sections for adjusting gravitational movements relative to each other and relative to the later section into juncture sealing positions automatically as said movable door section is moved into closed position.

References Cited by the Examiner UNITED STATES PATENTS 1,561,733 11/25 Lenk 110-173 X 2,306,832 12/42 Relling 110-180 X 2,386,565 10/45 Nissim 110-99 X 3,053,237 9/62 Carter 110173 X 3,115,336 12/63 Longenecker 110173 X 3,133,513 5/64 Hunt et al. 110173 FOREIGN PATENTS 724,116 2/55 Great Britain.

CHARLES SUKALO, Primary Examiner. JOHN J. CAMBY, Examiner. 

1. IN A FURNACE, THE COMBINATION COMPRISING A ROOF HAVING A PAIR OF SECTIONS, ONE OF WHICH IS MOVABLE, HINGE MEANS SUPPORTING SAID MOVABLE ROOF SECTION FOR PIVOTAL MOVEMENT RELATIVE TO THE OTHER ROOF SECTION, SAID MOVABLE SECTION DEFINING WITH SAID OTHER SECTION A DOORWAY AND CONSTITUTING A DOOR FOR SAID DOORWAY, SAID SECTIONS DEFINING THEREBETWEEN A JUNCTURE IN CLOSED POSITION OF SAID MOVABLE DOOR SECTION, TUBES FOR CARRYING HEAT EXCHANGE LIQUID LINING OPPOSITE SIDES OF SAID JUNCTURE, AND SEALING GRAVITATIONAL MOVEMENT RELATIVE TO SAID MOVABLE DOOR SECTION INTO SEALING POSITION BETWEEN THE TUBES ON OPPOSITE SIDES OF SAID JUNCTURE AUTOMATICALLY UPON THE CLOSING OF SAID MOVABLE DOOR SECTION, TO SEAL SAID JUNCTURE. 